Hydrogen atom abstraction

Hydrogen atom abstraction or hydrogen atom transfer (HAT) in chemistry is any chemical reaction in which a hydrogen free radical is abstracted from a substrate according to the general equation:

X^. + H-Y -> X-H + Y^.

Examples of HAT reactions are oxidative reactions in general, hydrocarbon combustion and reactions involving cytochrome P450 containing an iron(V)-oxo unit. The abstractor is usually a radical species itself. An example of a closed-shell abstractor is chromyl chloride. HAT can take place through proton-coupled electron transfer.^[1]

Non-radical Hydrogen Abstraction

It is reported in literature that during the synthesis of a Coelenterazine derivative, a non-radical hydrogen abstraction was observed on a substituted aminoimidazole in a typical Sandmayer hyroxilation condition.^[2]

References

^ Lai W.; Li C.; Chen H.; Shaik S. (2012). "Hydrogen-Abstraction Reactivity Patterns from A to Y: The Valence Bond Way". Angew. Chem. Int. Ed. 51: 5556–5578. doi:10.1002/anie.201108398.
^ Vece V.; Vuocolo G. (2015). "Multicomponent Synthesis of Novel Coelenterazine Derivatives Substituted at the C-3 Position". Tetrahedron. 71: 8781–8785. doi:10.1016/j.tet.2015.09.048.

[1] Lai W.; Li C.; Chen H.; Shaik S. (2012). "Hydrogen-Abstraction Reactivity Patterns from A to Y: The Valence Bond Way". Angew. Chem. Int. Ed. 51: 5556–5578. doi:10.1002/anie.201108398.

[2] Vece V.; Vuocolo G. (2015). "Multicomponent Synthesis of Novel Coelenterazine Derivatives Substituted at the C-3 Position". Tetrahedron. 71: 8781–8785. doi:10.1016/j.tet.2015.09.048.

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